Table 1.

Study characteristics. MMSE, the Mini-Mental State Examination; POD, postoperative delirium; RCT, randomized controlled trials

Study	Design	Surgery type	Sample size	Participant	initiation of MMSE	Cutoff point of MMSE	Reported outcomes of interest
Beloosesky 2002 [26]	Prospective cohort study	Hip surgery	153	≥65 yr	Before surgery	24	In-hospital mortality
Bliemel 2015 [27]	Prospective cohort study	Hip surgery	399	≥60 yr	Before surgery	27	1-year mortality
Brouquet 2010 [25]	Prospective cohort study	Abdominal surgery	118	≥75 yr	Before surgery	26	POD
Guo 2014 [29]	Prospective cohort study	Hip surgery	244	>60 yr	Before surgery	24	Total hospitalization days (surgery and rehabilitation)
							1-month/6-months/1- year mortality
Häkkinen 2007 [28]	Prospective cohort study	Hip surgery	117	≥65 yr	After surgery	24	Length of stay in orthopedic/rehabilitation ward
							1-year mortality
Huusko 2000 [19]	RCT	Hip surgery	243	≥65 yr	After surgery	24	3 month/1 year mortality
							Length of stay in rehabilitation ward
Jones 2017 [31]	Prospective cohort study	Hip surgery	383	≥65 yr	After surgery	18	6 months Mortality
							Length of stay in orthopedic wards
Kalisvaart 2006 [30]	Prospective cohort study	Hip surgery	603	≥70 yr	Before surgery	24	POD
Karni 2013 [33]	Prospective cohort study	Hip surgery	60	≥65 yr. Female	After surgery	24	Length of stay in rehabilitation ward
Kratz 2015 [32]	Prospective cohort study	general, abdominal, and trauma surgery	178	>70 yr	Before surgery	27	POD
Lee 2016 [7]	Retrospective cohort study	lumbar spine surgery	129	>65 yr	Before surgery	24	POD
							Length of stay in hospital
Moncada 2005 [35]	Prospective cohort study	Hip surgery	48	≥65 yr	After surgery	24	Length of stay in orthopedic/rehabilitation ward
							POD
Morghen 2011 [34]	Prospective cohort study	Hip surgery	386	≥65 yr	After surgery	24	Length of stay in rehabilitation ward
Osse 2012 [36]	Prospective cohort study	Cardiac surgery	125	≥70 yr	Before surgery	28	POD
Otano 2015 [38]	Prospective cohort study	Hip surgery	285	≥65 yr	After surgery	24	In-hospital mortality Length of stay in rehabilitation ward
Reissmüller 2006 [37]	Prospective cohort study	Cardiac surgery	107	≥60 yr	Before surgery	24	POD
Rolland 2004 [22]	Prospective cohort study	Hip surgery	61	≥70 yr	After surgery	20	Length of stay in rehabilitation ward
Ruggiero 2016 [21]	Prospective cohort study	Hip surgery	514	≥65 yr	After surgery	24	1-year mortality
Schaller2012 [23]	Prospective cohort study	Hip surgery	173	≥65 yr	After surgery	24	1 year mortality
Witlox 2009 [24]	Prospective cohort study	Hip surgery	76	≥75 yr	Before surgery	24	POD
Yukako 2016 [20]	Retrospective cohort study	Colorectal surgery	156	≥75 yr	Before surgery	24	POD